Elastomeric ear construction for disposable absorbent article

ABSTRACT

The use of a drawstring-like design for the elastomeric member in an absorbent article is disclosed. The elastomeric member is attached to the longitudinal axis of the article near its center and covers the back portion of the article forming ear-like structures that have fasteners attached to them so as to fix them to the front portion of the article.

BACKGROUND OF THE INVENTION

The present invention relates to the field of absorbent articles used for the containment of body fluids. More particularly the invention relates to the use of elastomeric ears for fitting these articles on the body of the wearer.

Disposable absorbent articles have long been used for the absorption of various kinds of bodily fluids. They have been used in various forms ranging from diapers for babies, to adult incontinence articles, to feminine health care products. Today, most of these articles employ the use of an absorbent pad sandwiched between a liquid permeable sheet and a liquid impermeable sheet. These articles may take various shapes and sizes depending upon their need and applicability. For example, a pad type structure may be used for feminine health care products. The article may be hourglass shaped for use as a baby diaper, or it may take the shape of pants when it is used for toilet training for young children, or as a convenience device for adults having difficulty controlling their bladder.

Considerable effort has been expended by engineers to increase the use of the absorbent articles. This effort has been directed towards increasing functionality of the article, for example by improving absorption, retention of multiple voids, less leakage, enhancing ease of use and wearer comfort, such as a improving fit and minimizing skin irritation. Further efforts include designing a better-looking product, by using printed backsheets and reducing the product's bulkiness. Other innovations include features such as visual indicators of ‘time to change’ the article, ‘glow in the dark’ articles and articles with skin conditioners etc.

Since such an article is usually worn throughout the day, it is very important to not only minimize skin irritation that may be caused by the article, but also to maximize the fit of the article on the body so as to increase the comfort of the wearer. Ease in wearing, cozy fitness for long periods of time, and freedom in body movement are just some of the desired features from such a product.

Diapers are one kind of absorbent article that have evolved over time from bulky, uncomfortable, leak prone, rectangular articles, to lightweight, long lasting, appealing looking products. Owing to the research and development in the field, the acceptability of diapers has increased to such an extent that they enjoy a 95% penetration in the US market.

One important area where significant development has occurred, is in the way the diaper is fitted to the body. The hourglass design is one such innovation that was adopted by the industry in the 1980s. In the hourglass configuration, the diaper has a near rectangular crotch region. Above and below this region (i.e. at the shorter side of the rectangle) are relatively broad front and rear portions of the diaper. These sections together cover the front (i.e. the area above the crotch and below the stomach) and back portion (i.e. the bottom) of the wearer. The top edge of these sections (i.e. the front and rear) together form the waist portion of the diaper.

In order to have better coverage of the side portion of the body when a diaper is worn, these sections are progressively being redesigned with flaps projecting outwardly from both sides of the diaper. These flaps or ‘ears’ not only give a fuller coverage to the body (and hence provides a better fit), but also provides a well-defined leg section.

The hourglass configuration as is commonly used today has relatively broad front and rear portions (with wing like protrusions) connected by a crotch section having an absorbent member. When a diaper is worn, it is positioned in such a way that the absorbent section covers the crotch of the wearer and the front section is folded over so as to cover the front portion of the wearer. The rear portion covers the bottom of the wearer. The outward projecting ears of the front portion (from the navel to the side of the body) are overlapped by the outwardly projecting ears from the rear portion (coming from the back of the body to the front). In this way, a full waist circle is formed. As mentioned earlier, the ears can be shaped in such a way so as to have well-defined leg openings.

In order for the diaper to stay in place there should be some way for the rear ears to be fixed to the front portion of the diaper. The industry has adopted various means for achieving this result, such as through the use of tapes and/or mechanical fasteners. Since fasteners such as tapes and other fasteners have a tendency to gradually loosen their grip during prolonged periods of wearing the diaper, it is desirable to have a configuration of ears and fasteners such that the diaper can be pulled and tightly fitted on the wearer. This would ensure a prolonged period of comfortable wearing.

U.S. Pat. No. 5,496,298 to Kuepper et al. discloses the construction of such ears. The ears disclosed in the reference are attached to the front and rear portions of the main body of the diaper. The ears are made of elastomeric material (for better body hugging fit), and are shaped to cover the side of the body (increasing leak protection). The ears are disclosed as being affixed to the body of the diaper along proximal edges at the outer periphery of the diaper. This type of attachment provides only limited room for expansion around the body of the wearer. Accordingly, the area available for increasing the waist fit in this configuration is only the ear portion. Therefore, increasing the stress on these ears can put a strain on the side of the body. Furthermore since a small portion of material is available for providing a proper fit, the material is required to be of high quality. High quality elastomers add to the cost of the article.

U.S. Pat. No. 6,648,868 to Sayama et al. discloses the use of two bands of elastic members at the top and bottom edge of the front as well as the rear portion of the diaper. Although this configuration may have better performance in terms of leak protection, the use of elastic at the edges would strain the edges and consequently cut into the skin, making it difficult to wear the article for prolonged periods of time.

US Patent Publication No. 2002151863 A1 to Toyoshima discloses the use of two elastic members at either side of the absorbent core. In such a configuration, the use of an elastic may irritate the skin. Furthermore, since the elastic is only provided along the sides of the article, the grip at the back of the body is not provided for.

Accordingly, it would be desirable to provide an absorbent article that not only has a better grip around the waist of the wearer, but is also minimally irritable to the skin. This would increase the prolonged continuous wearing of the article. It is also desirable to achieve such an article with minimal cost. The present invention has an objective to overcome the aforementioned drawbacks, and provide a better absorbent article.

Additional objectives of the present invention include providing a better fitting absorbent article, providing an absorbent article that is comfortable to wear for long periods of time, and providing a better fitting and comfortable absorbent article by using cost-effective material.

SUMMARY OF THE INVENTION

To achieve the aforementioned objectives and to overcome the drawbacks of the prior art, the present invention introduces the use of an elastomeric member with a drawstring-like design to secure the absorbent article to the wearer. Pursuant to the instant invention, an elastomeric member is attached at its center to the back portion of the absorbent article, near its longitudinal axis, and spans outwardly to either end of the article. The elastomeric member has fasteners attached at both its edges that assist in securing the “ears” to the main body of the article.

Since the elastomeric member provides support and fit from the back of the article to the sides, and covers a portion of the front body, the grip/fit provided by the improved design is significantly enhanced. Furthermore since the area covered by the improved design is greater than previous designs, the particular elastomer used can have lower elasticity levels and hence a lower cost. Elastomers with lower elasticity levels generally cannot be elongated to over 350% before breaking.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the top view of the absorbent article of one embodiment of the invention.

FIG. 2 is the longitudinal cross section of the absorbent article of the embodiment of FIG. 1.

FIG. 3 is the rear view of the embodiment of the absorbent article illustrated in FIG. 1.

FIG. 4 is the rear view of another embodiment of the invention.

FIG. 5 is the rear view of a further embodiment of the invention.

FIG. 6 is the rear view of a still further embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to absorbent articles that are disposable in nature. The term “disposable absorbent article” as mentioned herein refers to articles that absorb and contain body discharges. The articles are discarded after a first use and are not intended to be used more than once. The invention is more particularly described below with reference to hourglass shaped absorbent articles that are placed close to the body and wrapped over so as to form an underwear-like structure. However the invention is also applicable to other types of absorbent articles such as adult incontinent briefs, children training pants and the like.

The portions of the article can be described using the following terms. If the article is spread out flat on a table with the body-touching portion facing up, then the visible surface is referred to as the ‘top of the article’. The surface touching the table is referred to as the ‘bottom of the article’. The near-rectangular portion in the middle of the article is referred to as the ‘crotch section’. The outstretched portion is referred to as the ‘rear of the article’, and more particularly the ‘bottom-rear’ portion of the article covers the buttocks of the wearer. The portion of the article at the other end of the ‘crotch section’ is referred to as the ‘front portion’ of the article. The ‘bottom-front’ portion forms the facing portion of the article.

The present invention improves upon the articles of the prior art by introducing a drawstring-like elastomeric member that covers the whole back as well as the side of the wearer. The instant configuration provides a better fit and grip to the article. The materials that may be used for individual components may be chosen from a wide variety of suitable materials known in this field.

As a general rule, the elastomeric material used in the present invention is stretchable in at least one direction. Preferably, the elastomeric material is stretchable in two directions. When the elastomeric material is stretchable in a single direction, the stretch direction of the elastomeric material will be oriented so as to provide elastomeric forces which tend to pull the front and rear portions of the article towards one another such that the article is maintained about the waist of a wearer. The elastomeric material can comprise materials such as a stretch-bonded-laminate (SBL) material, a neck-bonded-laminate (NBL) material, an elastomeric film, an elastomeric foam material, or the like. For example, suitable meltblown elastomeric fibrous webs are described in U.S. Pat. No. 4,663,220 issued May 5, 1987, to T. Wisneski et al., the disclosure of which is hereby incorporated by reference in its entirety.

As used herein, reference to two materials or elements being “joined” refers to a process wherein the two materials or elements are directly joined to one another, or a process wherein the materials are indirectly joined to one another such as where both are joined to an intermediate element. Similarly, methods of joining two materials or elements include forming the elements or materials integrally, or attaching the elements together such as through the use of adhesives, sonic or thermal bonding, sewing, and the like. We shall now explain the invention with reference to the accompanying figures. Although reference herein is made to baby diapers, it will be appreciated that the invention is also applicable to all such products that have a waist region, such as training pants, adult incontinent articles and the like. While the instant invention is described by reference to diapers that have an hourglass configuration, the invention is also applicable to other kinds of configurations wherein a diaper fit is attained by changing the configuration at the waist, for example pant-type diapers and the like.

FIG. 1 illustrates an hourglass-shaped absorbent article 10 of this invention. The article 10 has a front portion 30 and a rear portion 40. A crotch portion 20 interconnects these two portions. The crotch portion is substantially rectangular in shape, and the front and rear portions are adjacent to the shorter edges of the crotch portion. It may be noted that the front, rear and crotch portions are used herein as merely indicative of various sections of the article. These portions are generally present as one single piece although they have different layers, and various portions of the article may have one or more layers.

The top layer, i.e. the layer on the top portion of the article, is a liquid permeable body liner 55. This is the portion of the article that touches the body of the wearer and it is therefore generally made of a soft material. The bottom most layer can be a liquid impervious sheet 60 that forms the visible surface of the article, or the bottom layer 60 can be a pervious hydrophobic sheet, provided that an impervious sheet is also used beneath the absorbent core. Interposed between these layers is an absorbent core 50 that has the functionality to absorb the body fluids. The rear portion 40 spans outwards and has elastomeric members called elastomeric ears 80 at respective left and right edges of the absorbent article. These elastomeric ears 80 have fasteners 90 attached to their edges. These fasteners are intended to engage coupling member 75 on the left and right edges of the front portion of the article or across the entire front portion.

When a diaper is fastened to the body of a wearer, the diaper is fastened in such a manner that the crotch region 20 of the diaper covers the crotch portion of the wearer. As mentioned earlier, the surface of the diaper that touches the body of the wearer is the liquid pervious sheet. The front portion 30 is pulled over to the front portion of the body of the diaper such that it covers the area of the stomach below the navel. The rear portion 40 covers the bottom of the wearer. The ears 80 are pulled over from behind such that they cover the side portion of the body using fasteners 90 that are fixed to coupling member 75 on the front portion of the diaper. Consequently, the left and right ears 80, the top edge of the rear portion 65, and the front portion 75, form a waist circle for the wearer. Additionally, the edges of the crotch portion 20 together with the ears 80 form the leg openings for the wearer. The article is further provided with elastic members at front and rear portions 85 and 70 so as to have a better fit. The tightening of the article around the waist is assisted by the elastomeric material that forms the ears 80 together with the fasteners 90 and 75. The fastening can be done at an appropriate place so as to form the exact waist size of the wearer. Furthermore, the article is also provided with elastic members 65 at the sides so as to prevent leakage from the sides. Leakage is prevented by the presence of members 65 and 70 at the top and bottom of the rear and front portions, respectively.

Elastomeric member 100 is attached to the article at its center 101, near the longitudinal axis 102 of the article. This elastomeric member spans outwards so as to form ear-like projections 80 at either edges of the absorbent article. Regions A1 and B1 denote the ears of the article, and regions A2 and B2 are the portions that cover the rear portion 40 of the article. Such a configuration makes the rear portion of the article (except for the attachment portion) stretchable, and hence offers a much better fit to the article around the waist. The attachment as mentioned herein may be done by a variety of suitable means such as by using adhesives, heat fusion, stitching, etc.

In the prior art disposable articles, stretching is primarily achieved through the ear portion 80, which puts a strain on the side portion of the body of the wearer. However, in the instant invention, the stress force as a result of stretching the ears is distributed from the longitudinal axis to the outer edges of the article (see arrows), minimizing the stress and pull on the body of the wearer. The reduction in this force makes the article less irritable to the skin, thereby increasing its capacity for prolonged wear.

Since the length of stretching required from the elastomeric members is now distributed over a greater length i.e. (A1+A2+B1+B2)>(A1+B1), the elastomeric member used may be less extensive and consequently, less costly, thereby reducing the overall cost of the article.

FIG. 2 shows the cross section of the article shown in FIG. 1. The bottom most layer is the liquid impermeable outer sheet 60 having outstretched elastomeric ears (not shown) with fasteners 90 attached to them. This outer sheet may be made from materials that are impermeable to liquids so that the liquid (body fluid) retained in the absorbent core does not escape through it. It may be manufactured from various kinds of polymers that are thin as well as comfortable to fold and feel. Furthermore, the sheet may be patterned or printed so as to increase the visual appeal of the article. The fasteners may be mechanical fasteners or tapes, etc. Mechanical fasteners include fasteners such as loops, hooks, buttons, snaps, latches etc. The fastener is used in coupling with its mating member attached to the front of the article. For example the fastener could have the hook and the mating member could have the loop in a typical hook and loop assembly.

The top layer in FIG. 2 is the liquid permeable body sheet 55. The body sideliner is made from a material that is not only porous for the body fluids (“insult”) to pass through, but is also soft to the skin. It may be made from any kind of woven or non-woven material, or a combination of these materials. The absorbent core 50 is attached between the outer sheet and the top layer. These two layers are predominantly in the crotch portion of the article. The core has a top that is the absorbent surface 95. This surface has fast absorption properties that quickly absorbs any discharged body fluid, which is then gradually absorbed by the core 50. The core retains the fluid until the article is disposed of. The core is made from various kinds of natural or synthetic hydrophilic materials having particle shapes and sizes so as to offer maximum absorption area and liquid retention duration. The core may be interposed with high absorbent materials such as silica gel, etc., so as to increase the liquid retention capacity. The top surface of the core may have an absorbent surface made from a material that absorbs the liquid much faster than the core, and transfers it to the core over a period of time.

The side portion of the article has elastic members 65 and leg cuffs 92 that result in a better fit of the diaper around the legs as well as preventing any leakage from the sides. The elastic members are formed by thin strands of elastic that collectively form the side portions of the article. The leg elastics may be straight, curved or gathered as desired so as to provide better covering to the under leg and thigh portion of the wearer.

The elastomeric member 100 is interposed between the non-permeable back sheet 60 and the liquid permeable top cover 55. The length of the elastomeric member extends beyond the length of the rear portion of the article so as to form ear like projections.

FIG. 3 shows the back view of a first embodiment of the article wherein the outer sheet 60 completely covers (but is not attached to) the elastomeric member 100. In such a configuration, the appearance of the article is not affected. Furthermore, in FIGS. 3, 4 and 5, the elastomeric member is one single piece attached at its center to the longitudinal axis of the article. From the axis, it projects to either side of the article and forms ear-like projections at the right and left edges of the article.

FIG. 4 shows the configuration of the article of the second embodiment of the invention. In this embodiment the elastomeric member 100 is a two-piece article, one piece A1+A2 of which is attached to the right side of the longitudinal axis 102 of the article, and spans outwardly to the right side of the article forming a right ear. The other side B1+B2 is attached to the left side of the longitudinal axis and forms the left ear of the article. In the aforementioned embodiments, the elastomeric member is cut in the shape of the rear portion of the article i.e. in the shape of outstretched ears reaching from the crotch portion of the diaper. Furthermore, the elastomeric member is sandwiched between the outer sheet and the body liner.

FIG. 5 shows another embodiment of the article in which a belt-like elastomeric member 100 is attached as the outermost layer extending over the outer sheet 60 of the article. As seen in the figure, the rear of the article is shaped like ears, and the belt-like elastomeric member 100 covers (but is not attached to) the length of these ears, thereby ensuring that any stretching applied on this member would stretch the ears. The same belt-like configuration may also be sandwiched between the outer sheet and body liner. Since the material used in the belt-like configuration is less than in a conventional design, further savings in costs are achieved.

FIG. 6 shows yet another embodiment of the invention in which the rear portion of the article has an attractive shape, and just covers the rear part of the body not the side. The elastomeric member 100 is shaped like a belt and spans to either side of the article. The elastomeric member just covers the waist region of the side of the body and fastens to the front portion of the article.

As can be seen from the above-illustrated embodiments, the article of this invention can include many different configurations. The aforementioned embodiments are merely illustrative and are not intended to limit the scope of the invention in any way. Various alternatives of the invention may exist, and the invention seeks to cover all such equivalents, including equivalents embodying the use of various materials. As may be apparent to those skilled in the art, various embodiments of the invention can be conceived and applied to various forms of absorbent articles without departing from the spirit, crux and focus of the invention. Accordingly, the scope of the invention is not bound by the appended claims, but includes all permissible equivalents therefore. 

1. A disposable absorbent article, said article comprising: a main body having a longitudinal axis with front and rear portions, the front and rear portions being connected by a crotch portion, and an elastomeric member attached to the front and/or rear portions of said article, near the longitudinal axis of said main body, in such a manner that said member projects radially outwards from the longitudinal axis to either side of the article.
 2. The article as claimed in claim 1, wherein the main body comprises: a liquid impervious outer sheet, a liquid permeable body liner, and an absorbent core disposed between said outer sheet and said body liner, said absorbent core lying predominantly in the crotch region and being substantially rectangular in shape, and said front and rear portions of said main body being broader and spread out in a wing-like manner from the sides of the crotch portion.
 3. The article as claimed in claim 1, wherein said elastomeric member is attached at its center near the longitudinal axis of the article, and is interposed between the body liner and the outer sheet.
 4. The article as claimed in claim 1, wherein said elastomeric material is attached at its center near the longitudinal axis of the article on the outer sheet of the article.
 5. The article as claimed in claims 1 or 3, wherein said elastomeric member projects outwardly so as to form ear-like structures.
 6. The article as claimed in claim 1, wherein said article is a diaper having fasteners attached to either edge of the elastomeric material so as to affix the elastomeric material to the outer cover of the article.
 7. The article as claimed in claim 6, wherein said fasteners include buttons, adhesive tapes, hooks and loops, snaps and latches.
 8. The article as claimed in claim 1, wherein said article has a pant-like structure wherein said front and rear portions of the main body are permanently joined at their respective left and right edges.
 9. The article as claimed in claim 1, wherein said elastomeric member has two symmetrical portions that are attached near the longitudinal axis of the article and project radially outward.
 10. The article as claimed in claim 1, wherein said attachment is by the use of adhesive substance, heat fusion, or stitching.
 11. The article as claimed in claim 1, wherein said elastomeric material has low elasticity.
 12. The article as claimed in claim 11, wherein said elastomeric material includes spandex elastic strands and elastic strands. 